I. Blumcke et al., The CD34 epitope is expressed in neoplastic and malformative lesions associated with chronic, focal epilepsies, ACT NEUROP, 97(5), 1999, pp. 481-490
The etiology and pathogenesis of complex focal lesions associated with chro
nic, intractable epilepsy are largely unknown. Some data indicate that malf
ormative changes of the central nervous system may preceed the development
of gangliogliomas and other epilepsy-associated neoplasms. In the present i
mmunhistochemical study, we have examined epilepsy-associated lesions for C
D34, a stem cell marker transiently expressed during early neurulation. Sur
prisingly, most tissue samples from patients with chronic epilepsy (n = 262
) revealed neural cells immunoreactive for CD34. Prominent immunoreactivity
was detected in gangliogliomas (74%), low-grade astrocytomas (62%) and oli
godendrogliomas (59%). Only 52% of non-neoplastic, malformative pathologies
, such as glio-neuronal hamartias or hamartomas showed solitary or small cl
usters of CD34-immunoreactive cells. None of the adult control tissues (n =
22), none of the specimens obtained from the developing human brain (n = 4
4) and none of those tumor samples from patients without epilepsy (n = 63)
contained CD34-immunoreactive neural cells. However, a malignant teratoma w
ith microscopic features of early neural differentiation displayed a focal
CD34-immunoreactive staining pattern. The majority of CD34-immunoreactive c
ells co-localized with S-100 protein and a small subpopulation was also imm
unoreactive for neuronal antigens. CD34 may, thus, represent a valuable mar
ker for the diagnostic evaluation of neoplastic and/or malformative patholo
gical changes in epilepsy patients. The CD34 immunoreactivity of these lesi
ons indicates an origin from dysplastic or atypically differentiated neural
precursors. Further studies may elucidate the functional significance of C
D34 expression during the pathogenesis of epilepsy-related focal lesions as
well as during neurogenesis.